Now Joseph had been brought down to Egypt: [Scripture] returns to the previous topic, which it had interrupted in order to juxtapose the demotion of Judah with the selling of Joseph, to imply that because of him (Joseph), they (his brothers) demoted him (Judah) from his high position; and also to juxtapose the incident of Potiphar’s wife with the incident of Tamar, to tell you that just as that one [the incident of Tamar] was meant for the sake of heaven, so too this one [the incident of Potiphar’s wife] was meant for the sake of heaven. For she saw through her astrology that she was destined to raise children from him (Joseph), but she did not know whether [they would be] from her or from her daughter. [From Gen. Rabbah 85:2]

and all he had: Heb. וְכָל-יֶשׁ-לוֹ. This is elliptical. The word אִשֶׁר is missing. [It should read: וְכָל-אִשֶׁר יֶשׁ-לוֹ.] [from targumim]

וכל יש לו: הרי לשון קצר, חסר אשר:

5Now it came to pass that since he had appointed him over his house and over all that he had, the Lord blessed the house of the Egyptian for Joseph's sake, and the blessing of the Lord was in all that he had, in the house and in the field.

and he knew nothing about what was with him: He did not pay attention to anything.

ולא ידע אתו מאומה: לא היה נותן לבו לכלום:

except the bread: That is his wife, but [Scripture] speaks euphemistically. [From Gen. Rabbah 86:6]

כי אם הלחם: היא אשתו, אלא שדבר בלשון נקיה:

and Joseph had handsome features: As soon as Joseph found himself [in the position of] ruler, he began eating and drinking and curling his hair. Said the Holy One, blessed be He: “Your father is mourning and you curl your hair! I will incite the bear against you.” Immediately afterwards“his master’s wife lifted up her eyes.” [from Tanchuma Vayeshev 8]